Describe the role of the skin and mucous membranes in nonspecific resistance

the skin and mucous membranes are the first line of defense: non- specific mechanical barriers to infection. composition- physical/mechanical defenses of the skin and mucous membranes. Innate immunity, nonspecific
skin= great physical barrier, oils (sacks of keratin on epidermis lubricate, metabolized by microbes as a food source) keratin is a tight water proof barrier that is like armor and is hard to digest , natural flora (staph, strep, candida albicans) occupies niches that make it difficult for pathogens to take hold. , pH (4-6) discourages the growth of many pathogens, sweat contains salt, urea and lysozyme, .
mucous membranes= respiratory system (nasal, throat, trachea, bronchii, alveoli, mucus, hair, sneeze, cilia) GI tract (saliva, protects from tooth decay, mucous membranes, pH extremes, peristalsis) UG tract (urigenital tract, urine system, acidic pH (4.3-4.9) Mucus membranes line the GI, respiratory and genitourinary tracts. The epithelial lay secretes a fluid called mucus, a slightly viscous glycoprotein produced by goblet cells of a mucous membrane. It prevents the tracts from drying out and serves as a mechanical barrier to microbes.

Differentiate mechanical from chemical factors, and list examples of each.

a physical barrier relies on the material it is made of to block the passage of "whatever" in and out or through the barrier. What can or cannot pass through is dictated by the size of the spaces between the molecules, or holes, in the physical barrier. A chemical barrier is made up of chemicals, or enzymes, and more, than do not allow certain chemicals to pass through, For example, the chemical kills the germ before it can pass into a cell, or the barriers of the cell, and parts inside the cell , dictate what can and cannot penetrate the cell, if all works well.
examples: skin (epidermis, dermis) mucous membranes, hairs, cilia, peristalsis, defecation, vomiting.
chemical factors- vaginal secretions, gastric juice, perspiration, sebum, urine

Describe the role of the normal flora in nonspecific resistance

Normal flora organisms may keep pathogen numbers under control by:
1. Competing with them for nutrients
2. Producing substances harmful to the pathogens
3. Altering environmental conditions so that pathogens are inhibited (pH and oxygen availability)

Describe the process of phagocytosis and include the stages of adherence and ingestion.

chemotaxis and adherence of microbe to phagocyte- adherence is the attachment of the phagocytes plasma membrane tot eh surface of the microorganism or other foreign material.
ingestion of microbe by phagocyte
formation of phagosome
fusion of the phagosome with a lysosome to form a phagolysosome
digestion of ingested microbe by enzymes
formation of residual body containing indigestible material
discharge of waste materials
phagocytes migrate to a site of infection and can destroy the infecting bacteria. The phases of phagocytosis are chemotaxis, adherence, ingestion, and digestion.

Describe the cause and effects of fever

fever- an abnormally high body temperature, a third component of the second line of defense. the most frequent cause of fever is infection from bacteria (and their toxins) or viruses. Fevers help fight off infection High temperatures speed up the bodies reactions it may help the body repair tissues more quickly

define inflammation and list its characteristics

what are interferons? Discuss their roles in innate immunity

a specific group of cytokines. are antiviral proteins produced by certain animal cells in response to a viral infection. stimulates macrophage activity
would inhibit bacteria
would prevent adherence of N. gonorrhoeae
S. pyogenes would not be able to attach to host cells and would be more susceptible to phagocytosis

Why do serum levels of iron increase during an infection? What can a bacterium do to respond to high levels of transferrin?

serum levels of iron increase during an infection because
Higher levels of tranferrin decrease the iron levels available to microbes and most pathogenic bacteria require adequate amounts of iron for their vegetative growth and reproduction.